Who uses distributed systems?

Who exactly are the primary users of distributed systems in today's world? Are they predominantly tech giants like Google, Amazon, and Facebook who rely on these systems to manage their massive data centers and user bases? Or do they extend to smaller companies, startups, and even individual developers looking to harness the power of decentralization and scalability? Additionally, are there specific industries that have embraced distributed systems more than others, and if so, what are the key factors driving this adoption? Understanding the who, what, and why behind the usage of distributed systems is crucial in assessing their impact and potential for future growth.